Established in 1905, Las Vegas was incorporated as a city in 1911. At the close of the 20th century, Las Vegas was the most populous American city founded in that century (a distinction held by Chicago in the 19th century). The city's tolerance for various forms of adult entertainment earned it the title of Sin City, and this image has made Las Vegas a popular setting for films and television programs. There are numerous outdoor lighting displays on Fremont Street, as well as elsewhere in the city.

Las Vegas started as a stopover on the pioneer trails to the west, and became a popular railroad town in the early 20th century. It was a staging point for mines in the surrounding area, especially those around the town of Bullfrog, that shipped goods to the rest of the country. With the proliferation of the railroads, Las Vegas became less important, but the completion of the nearby Hoover Dam in 1935 resulted in growth in the number of residents and increased tourism. The dam, located 30 mi (48 km) southeast of the city, formed Lake Mead, the largest man-made lake and reservoir in the United States. The legalization of gambling in 1931 led to the advent of the casino hotels for which Las Vegas is famous. Major development occurred in the 1940s, "due almost entirely" to the influx of scientists and staff from the Manhattan Project, an atomic bomb research project of World War II. Atomic test watching parties were sometimes thrown.[18] American organized crime figures such as Benjamin "Bugsy" Siegel and Meyer Lansky managed or funded most of the original large casinos.[19] The rapid growth of Las Vegas is credited with dooming the gambling industry development of Galveston, Texas; Hot Springs, Arkansas; and other major gambling centers in the 1950s.[20]

Las Vegas is situated within Clark County in an arid basin on the desert floor, surrounded by dry mountains. The Spring Mountains lie to the west. Much of the landscape is rocky and dusty; the environment is dominated by desert vegetation and some wildlife, and the area is subject to torrential flash floods. The elevation is around 2,030 ft (620 m) above sea level. According to the United States Census Bureau, the city has a total area of 135.86 sq mi (351.9 km2), of which 135.81 sq mi (351.7 km2) is land and 0.05 sq mi (0.13 km2) (0.03%) is water.

Within the city there are many lawns, trees, and other greenery. Due to water resource issues, there is now a movement to encourage xeriscapes. Another part of the water conservation efforts include scheduled watering groups for watering residential landscaping. A U.S. Environmental Protection Agency grant in 2008 funded a program that analyzed and forecast growth and environmental impacts through the year 2019.

The summer months of June through September are very hot and mostly dry, with a July daily average temperature of 92.5 °F (33.6 °C), while night-time temperatures often remain above 80 °F (27 °C). There are an average of 134 days of 90 °F (32 °C)+ highs, and 74 days of 100 °F (38 °C)+ highs,[22] with most of the days in July and August exceeding the latter benchmark, and only occasionally failing to reach the former. Humidity is very low, often under 10%.

Las Vegas' winters are of short duration and the season is generally mild, with December, the coolest month, averaging 47.7 °F (8.7 °C). The mountains surrounding Las Vegas accumulate snow during the winter but snow is rare in the Las Vegas Valley itself, although on December 16, 2008, Las Vegas received 3.6 inches (9.1 cm).[23] Temperatures reach the freezing mark on 16 nights of the year but rarely sink to 20 °F (−7 °C).[22]

Annual precipitation in Las Vegas is about 4.2 in (110 mm), which on average occurs on 26–27 days per year.[22] Most of the precipitation falls in the winter, but the wettest month (February) has on average only 4 days of precipitation.

The city's most populous ethnic group, non-Hispanic Whites,[28] have proportionally declined from 72.1% of the population in 1990 to 47.9% in 2010, but their total numbers have increased.[29]

Hawaiians and Las Vegans sometimes refer to Las Vegas as the "ninth island of Hawaii" because so many Hawaiians have moved to the city.[30]

As of the census[31] of 2010, there were 583,756 people, 211,689 households, and 117,538 families residing in the city. The population density was 4,222.5 /sq mi (1,630.3 /km2). There are 190,724 housing units at an average density of 1,683.3 /sq mi (649.9 /km2).

As of 2006, there were 176,750 households, out of which 31.9% had children under the age of 18 living with them, 48.3% were married couples living together, 12.2% had a female householder with no husband present, and 33.5% were non-families. 25.0% of all households were made up of individuals and 7.5% had someone living alone who was 65 years of age or older. The average household size was 2.66 and the average family size was 3.20.

In the city the population was spread out with 25.9% under the age of 18, 8.8% from 18 to 24, 32.0% from 25 to 44, 21.7% from 45 to 64, and 11.6% who were 65 years of age or older. The median age was 34 years. For every 100 females there were 103.3 males. For every 100 females age 18 and over, there were 102.5 males.

The median income for a household in the city was $53,000 and the median income for a family was $58,465.[32] Males had a median income of $35,511 versus $27,554 for females. The per capita income for the city was $22,060. About 6.6% of families and 8.9% of the population were below the poverty line, including 5.4% of those under age 18 and 6.3% of those age 65 or over.

Las Vegas is one of the most stressful cities in the U.S., according to a 2004 study, and has one of the highest divorce rates.[33][34] The city's high divorce rate is not wholly due to Las Vegans themselves getting divorced. Since divorce is easier in Nevada than most other states, many people come from across the country for the easier process. Similarly, Nevada marriages are notoriously easy to get. Las Vegas has one of the highest marriage rates of U.S. cities, with many licenses issued to people from outside the area (see Las Vegas weddings).

The major attractions in Las Vegas are the casinos and the hotels. Most of the hotel casinos are in the city's downtown area, which has been the focal point of the city's gaming industry since its early days.

Most casinos are downtown on the Fremont Street Experience, The Stratosphere being the major exception. Fremont East, adjacent to the Fremont Street Experience, was granted variances to allow bars to be closer together, similar to the Gaslamp Quarter of San Diego, the goal being to attract a different demographic than the Strip attracts.

The gambling and entertainment industry in Las Vegas is mostly focused in the Las Vegas Strip. The Strip is not actually located in city limits, but instead in the surrounding unincorporated communities of Paradise and Winchester. The largest and most notable casinos and buildings are located there.

When The Mirage opened in 1989, it started a trend of major resort development of the southern portion of the Las Vegas Strip outside of the city. This resulted in a drop in tourism in the downtown area, but many recent projects and condominium construction have increased the number of visitors to downtown.

An effort has been made by city officials to diversify the economy by attracting light manufacturing, banking, and other commercial interests. The lack of state individual and corporate income tax and very simple incorporation requirements have fostered the success of this effort.

With the Strip expansion in the 1990s, Downtown Las Vegas (which has maintained an old Las Vegas feel) began to suffer. The city made an effort to turn around the fortunes of downtown. The city successfully lured the Internal Revenue Service operations from western side of the city to a new downtown area building that opened in April 2005. The IRS move was expected to create a greater demand for additional businesses in the area, especially in the daytime hours. The Fremont Street Experience (FSE) was built in an effort to draw tourists back to the area, and has been popular. Since the recession began in 2008, many of these shops have closed. The multi-level Neonopolis closed their 11 theaters and nearly all retail stores. Many high-rise condo projects have been under construction, but one of the highest profile buildings, The Streamline Towers, went into bankruptcy.

In 2004 the city partnered with Cheetah Wireless Technologies and MeshNetwork to pilot a wide-area mobile broadband system. The pilot system is installed downtown, around the Fremont Street Experience. On a lot adjacent to the city's 61 acre site, the World Market Center opened in 2005. It was intended as a preeminent furniture wholesale showroom and marketplace to compete with the current furniture market capital of High Point, North Carolina.

On October 23, 2006, plans were unveiled to build a World Jewelry Center in Symphony Park. Similar to the World Market Center, the WJC will be a one stop shop for jewelry trade shows from around the world. The project proposes a 57-story, 815 ft (248 m) office tower.[37] As of 2009 the project was still on hold.[38]

Las Vegas decided to build a new city hall in the late 2000s. This had several consequences. One is that the Las Vegas Metropolitan Police Department, which shared city hall, would have to find a new location. A second is that the old building would be vacated, with a potential negative impact on the downtown area. The police department elected to build a headquarters building in another part of the city and consolidate most of its operations in one place. This increased the department's presence within the city since it would be moving in employees not presently working in the city. The second problem was addressed when the city and Zappos reached an agreement for Zappos to move its headquarters into the old city hall.

On the first Friday of each month, the "First Friday" celebration is held, which exhibits the works of local artists and musicians in a section of the city's Downtown region called the "Arts District".[39]

The Thursday prior to First Friday is known in the 18b Arts District as "Preview Thursday". This evening event highlights new gallery exhibitions just opening throughout the district.

The $485 million Smith Center for the Performing Arts is located downtown in Symphony Park. The center hosts Broadway shows and other major touring attractions as well as orchestra, opera, ballet and dance performances.

Las Vegas does not have major-league sports, although the metropolitan population is as large or larger than many cities that have them. The two main reasons are concern about legal sports betting and competition for the entertainment dollar. The only minor league sports team that plays in the City of Las Vegas is baseball's Las Vegas 51s of the Pacific Coast League, the AAA farm club of the New York Mets.

The City of Las Vegas government operates as a council–manager government. The Mayor sits as a Council member-at-large and presides over all of the City Council meetings. In the event that the Mayor cannot preside over a City Council meeting, the Mayor Pro-Tem is the presiding officer of the meeting until such time as the Mayor returns to his seat. The City Manager is responsible for the administration and the day-to-day operation of all of the municipal services and city departments. The City Manager maintains intergovernmental relationships with federal, state, county, and other local governments.

Primary and secondary public education is provided by the Clark County School District, which is the fifth most populous school district in the nation (projected enrollment for the 2007–2008 school year was 314,000 students in grades K–12).

A bus rapid transit link in Las Vegas called the Strip & Downtown Express (previously ACE Gold Line[44]) with limited stops and frequent service was launched in March 2010, and connects Downtown Las Vegas, the Strip, the Las Vegas Convention Center, and Town Square. In addition, the Las Vegas Monorail connects different casinos on the Strip and with a planned extension to Las Vegas International Airport.

Las Vegas Boulevard divides the east–west streets from the Las Vegas Strip to near the Stratosphere, then Main Street becomes the dividing line from the Stratosphere to the North Las Vegas border, after which the Goldfield Street alignment divides east and west.

On the east side of Las Vegas, block numbers between Charleston Boulevard and Washington Avenue are different along Nellis Boulevard, which is the eastern border of the city limits.

The Union Pacific Railroad is the only Class I railroad to provide rail freight service to the city. Until 1997, the AmtrakDesert Wind train service ran through Las Vegas using the Union Pacific Railroad tracks. Amtrak service to Las Vegas goes to Needles, California and continues on Amtrak's Thruway Motorcoach bus service. Plans to restore Los Angeles to Las Vegas Amtrak service using a Talgo train were discussed in the late 1990s, but the plan was not implemented. In November 2012 Las Vegas Railway Express announced an agreement with Union Pacific Railroad to provide passenger service from Fullerton, California to Las Vegas using the Union Pacific Railroad tracks. Known as the "X Train", regular service is expected to start in 2014.[46] The Las Vegas Amtrak station was located in the Plaza Hotel; it held the distinction of being the only train station in the US that was located in a casino.